#region License, Terms and Author(s)
//
// TempRESS - TEMPlate Rendering Engine that's Small and Simple 
// Copyright (c) 2009 Atif Aziz. All rights reserved.
//
//  Author(s):
//
//      Atif Aziz, http://www.raboof.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

namespace Tempress
{
    #region Imports

    using System;
    using System.Collections.Generic;
    using System.IO;

    #endregion

    public sealed class CompiledTemplate
    {
        internal delegate void ProcessHandler(object[] args, TextWriter writer);

        private readonly ProcessHandler processor;

        internal CompiledTemplate(ProcessHandler processor, IEnumerable<TemplateArgument> arguments)
        {
            this.Arguments = TemplateArgumentCollection.ReadOnly(arguments);
            this.processor = processor;
        }

        public TemplateArgumentCollection Arguments { get; private set; }

        public void Process(IDictionary<string, object> args, TextWriter writer)
        {
            this.processor(CreateOrderedArgumentsArray(Arguments, args), writer);
        }

        private static object[] CreateOrderedArgumentsArray(ICollection<TemplateArgument> formals, IDictionary<string, object> actuals)
        {
            var values = new object[formals.Count];
            var index = 0;

            foreach (var formal in formals)
            {
                object value;
                if (!actuals.TryGetValue(formal.Name, out value))
                    throw new ArgumentException("Template argument " + formal.Name + " was not specified");
                values[index++] = value;
            }

            return values;
        }
    }
}